Ask A Scientist© Astronomy Archive

Question:
Dear Newton,
I am a fifth grader at Hollymead Elementary School.
Is it true that the stars we see may already be burned out?  And if you were up
close to a star, would it be as bright as it is on earth?
pamela dolgin

Answer:  Well, there are all sorts of different stars in the sky, some of them
much bigger and brighter than our sun (if we were as close to them as we are to
our sun), and some of them much smaller and dimmer. The big bright ones are the
ones that die first (usually in a big explosion). Since our galaxy is only about  100,000
light-years across, very few of the regular stars we can see would have blown up 
in the time it takes for their light to reach us. Even the short-lived ones live 
for millions of years. You would have to go to the next galaxy to start to see a  significant fraction
of stars that have died even though we still see their light. All this of course 
is assuming that our calculations about the life-times of stars are correct.
Asmith